Land-based sources of pollution (LBSP) are considered a substantial threat to coral reef ecosystems, and sedimentation (from dredging and/or runoff) is commonly acknowledged to be one of the primary causes of coral reef ecosystem degradation worldwide (Rogers 1990; Field et al. 2008). The combination of suspended, re-suspended, and deposited sediment act to limit coral growth, feeding, photosynthesis, recruitment, and survivorship (Fabricius, 2005). However, there has been very limited research that connects management actions taken in watersheds to downstream impacts in coral reef areas. In fact a recent global review concluded that "examples of watershed management demonstrating the halting or reversing of coral reef decline are not readily available" (Kroon et al. 2014). The efforts described here were implemented proactively to provide baseline data for pertinent variables - sediment loading and deposition, coral community structure and demographics, and chemical contaminant loads - ahead of interventions to reduce LBSP so that managers can evaluate their efficacy.
The primary purpose of this document is to provide local and federal partners with baseline information, survey methods, key findings, and recommended actions to support continued monitoring efforts to evaluate the effectiveness of management actions taken at the Samoa Maritime quarry in Faga'alu, American Samoa to reduce land-based sources of pollution inputs, specifically excess sedimentation, to the coral reefs in Faga'alu Bay. To carry out these baseline assessments, technical and scientific experts from the National Oceanic and Atmospheric Administration (NOAA) and San Diego State University (SDSU) collaborated to gather data to share with local management authorities in American Samoa. This document summarizes work completed between 2012 and 2014, and was coordinated and funded by the NOAA Coral Reef Conservation Program (CRCP) to gather data and information before management interventions such as drainage systems, alternative ground cover, and retention ponds were installed at the quarry. To quantify effectiveness of these interventions, additional long-term monitoring of sediment loads in Faga'alu Stream and coral community structure will be needed for comparison with the baselines presented here.
Citation: S. Holst Rice, A. Messina, T. Biggs, B. Vargas-Angel, and D. Whitall. 2016. Baseline Assessment of Faga'alu Watershed: A Ridge to Reef Assessment in Support of Sediment Reduction Activities and Future Evaluation of their Success. Silver Spring, MD: NOAA Coral Reef Conservation Program. NOAA Technical Memorandum CRCP 23. 44 pp. DOI: 10.7289/V5BK19C3